I have AVG set to scan at 08:00, when there is rarely anything happening with this machine, it takes 23 minutes for a complete scan.
On the rare occasions when the machine is in use when it runs, it does slow the machine down somewhat but not so much that it makes working uncomfortable.
Using it just to scan a folder suspected of harbouring a virus is done in an instant.
TrendMicro Housecall is a free online scan that will also do a spyware check. No clunky and I would argue unnecessary realtime protection. I scan my computer a couple times a year and it takes about half an hour.
Like TimeWinder, I say just get rid of the silly antivirus and rely on good practices. Use anything but Outlook for email, and something other than IE as your main browser (you will still need IE for some web sites like Housecall).
I think the virus thing is way over exaggerated. Spyware and hardware failure are much more of a problem. Reinstalling windows is often the best solution to all these problems anyways. Set restore points in windows and back up or simply isolate your data from the windows partition.
In the past eight years Ive had one virus infection, about four real spyware infections (not just cookies), two motherboard failures, two harddrive failures. Ive seen endless problems with friends computers running norton or other AV software for a hazard that I dont even think is significant.
I use Trend-Micro Internet Security. I used to have McAfee, and would never go back to it. Trend-Micro is much better and has never let me down.
If you have a single machine connected to a router that incorporates a firewall, you don’t, strictly speaking, need top install a personal software firewall on your PC, although doing so will often enable you to investigate and control what processes are communicating and how.
If you have a single machine connected directly to a cable or ADSL modem, you absolutely need a firewall. Windows firewall is pretty adequate, but doesn’t tell you anything about what is happening. For that, you need to install a personal software firewall, and turn off the Windows one - if you have two software firewalls running, they can potentially break each other, leaving you unprotected.
Forget what people say about ‘software firewalls’ being weak and ‘hardware firewalls’ being strong; for the most part, they’re talking bollocks, because the ‘hardware firewall’ in the home router they’re talking about * is actually a software firewall* (well, *firmware, but it’s the same difference) - it just happens to run on the router’s own hardware, and this could quite possibly be weaker than the software firewall on your PC, because the router firmware is typically more difficult (or inconvenient, frightening or just plain neglected) to upgrade than is the software on your machine.
If you have a home router with more than one computer attached, and particularly if you are not in absolute control of all of the machines on your home LAN, then you need a personal firewall on your computer, because an inappropriate action (for example, clicking on an infected email attachment) by one of the other users could render their computer compromised and, having infected a machine behind your firewall, there are ways in whcih malware can copy itself around a network without invitation.
You didn’t say how big your hard drive is, or how full it is, but if it is typical, five hours would indicate a performance problem that is slowing down AVG (or any anti-virus scanner).
Try cleaning up and defragging your hard drive before you run AV scanner. I like Ccleaner for clearing the hard drive of junk files; it also has a reliable registry cleaner as well. Diskeeper Lite for defragmenting your hard drive is more efficient than the one that comes with Windows. Both programs are freeware, and have no spyware attached.